快速-热挤压工艺对细晶和传统钨合金组织与性能的影响  

Effect of Rapid Hot Extrusion on Microstructure and Mechanical Properties of Fine-Grained Tungsten Alloy and Coarse-Grained Tungsten Alloy

作　　者：范景莲[1] 杨昌麟[1] 龚星[1] 丁飞[1] 

机构地区：[1]中南大学粉末冶金国家重点实验室,湖南长沙410083

出　　处：《稀有金属材料与工程》2013年第2期372-376,共5页Rare Metal Materials and Engineering

基　　金：国家杰出青年科学基金(50925416);国家自然科学基金创新群体项目资助(51074187)

摘　　要：研究了快速-热挤压工艺对细晶93W-4.9Ni-2.1Fe、细晶93W-4.9Ni-2.1Fe+0.03%Y以及传统粗晶93W-4.9Ni-2.1Fe合金的显微组织和力学性能的影响。结果表明:经过快速热挤压后,合金的综合力学性能较烧结态合金显著提高,而且初始晶粒尺寸对挤压后合金性能影响非常显著,在相同的挤压条件下,挤压态细晶93W-4.9Ni-2.1Fe+0.03%Y的抗拉强度达到1570MPa,延伸率为6.5%,硬度HRC45.2;而挤压态传统93W-4.9Ni-2.1Fe合金的抗拉强度、延伸率和硬度分别只有1260MPa、5.6%和39.1。显微组织观察分析表明,与传统钨合金相比,在相同变形量的情况下,细晶93W-4.9Ni-2.1Fe+0.03%Y钨合金的纤维化程度更高,钨颗粒长细比达到6.8。TEM观察表明挤压后细晶钨合金的钨相形成了亚晶组织,而传统钨合金有大量位错缠结于钨相中;此外,由于充分的动态回复-再结晶,细晶和传统钨合金的粘结相位错密度很低。The effect of rapid hot extrusion on the microstructure and mechanical properties of fine-grained （10-20 μm） 93W-4.9Ni-2.1Fe, fine-grained 93W-4.9Ni-2.1Fe＋0.03%Y and traditional coarse-grained （40-45 μm） 93W-4.9Ni-2.1Fe alloy was investigated. The results show that after rapid hot extrusion, the comprehensive mechanical properties of the alloys are significantly enhanced compared with the as-sintered alloys. The initial grain size has a profound effect on the mechanical properties of as-extruded alloys. With the same extrusion processing parameters, the ultimate tensile strength （UTS）, elongation and hardness of the as-extruded fine-grained 93W-4.9Ni-2.1Fe＋0.03%Y alloy reached 1570 MPa, 6.5% and 45.2 （HRC） respectively. However, the ultimate tensile strength （UTS）, elongation and hardness of the as-extruded coarse-grained alloy were 1260 MPa, 5.6% and 39.1. Microstructure observation shows that compared with the traditional coarse-grained alloy, the fibrous degree of the as-extruded fine-grained alloy is much larger under the condition of the same deformation degree. Moreover, the aspect ratio of the tungsten particles in the as-extruded fine-grained 93W-4.9Ni-2.1Fe＋0.03%Y alloy achieves 6.8, which is one time larger than that of the as-extruded traditional coarse-grained alloy. TEM shows that after hot extrusion, many subgrains could be observed in fine-grained tungsten phase and numerical dislocations tangled in coarse-grained tungsten phase. In addition, the dislocation density of both kind of matrix is low because of sufficient dynamical recovery-recrystallization.

关 键 词：细晶93W合金 快速-热挤压 形变强化 

分 类 号：TG379[金属学及工艺—金属压力加工]